We developed a novel method for fabrication of glass micromodels with varying depth (2.5-D) with no additional complexity over the 2-D micromodels' fabrication. Compared to a 2-D micromodel, the ...2.5-D micromodel can better represent the 3-D features of multi-phase flow in real porous media, as demonstrated in this paper with three different examples. Physically realistic capillary snap-off and the formation of isolated residual oil droplets were realized, which is not possible in 2-D micromodels. Droplet size variation during an emulsion flooding was investigated on the 2.5-D micromodel, showing that the droplet size decreases sharply at the inlet, with little change in size downstream of the micromodel. Displacement of light oil with ultra-low interfacial tension (IFT) surfactant was conducted in the 2.5-D micromodel, where we were able to visualize the generation and flowing of a microemulsion phase, which agrees with, and explains observations in experiments of more complex porous media.
Tests for SARS-CoV-2 are crucial for the mass surveillance of the incidence of infection. The long waiting time for classic nucleic acid test results highlights the importance of developing ...alternative rapid biosensing methods. Herein, we propose a fiber-optic biolayer interferometry-based biosensor (FO-BLI) to detect SARS-CoV-2 spike proteins, extracellular domain (ECD), and receptor-binding domain (RBD) in artificial samples in 13 min. The FO-BLI biosensor utilized an antibody pair to capture and detect the spike proteins. The secondary antibody conjugated with horseradish peroxidase (HRP) reacted with the enzyme substrate for signal amplification. Two types of substrates, 3,3'-diaminobenzidine (DAB) and an advanced 3-Amino-9-ethylcarbazole (i.e., AMEC), were applied to evaluate their capabilities in enhancing signals and reaching high sensitivity. After careful comparison, the AMEC-based FO-BLI biosensor showed better assay performance, which detected ECD at a concentration of 32-720 pM and RBD of 12.5-400 pM in artificial saliva and serum, respectively. The limit of detection (LoD) for SARS-CoV-2 ECD and RBD was defined to be 36 pM and 12.5 pM, respectively. Morphology of the metal precipitates generated by the AMEC-HRP reaction in the fiber tips was observed using field emission scanning electron microscopy (SEM). Collectively, the developed FO-BLI biosensor has the potential to rapidly detect SARS-CoV-2 antigens and provide guidance for "sample-collect and result-out on-site" mode.
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•Novel fabrication methods are combined to make a core-scale micromodel for EOR.•Long micromodels capture core-scale physics such as the formation of oil banks.•Increasing viscosity of displacing ...phase in long micromodels increases the amount of oil recovered at breakthrough.
Fluid injection experiments in rocks, commonly referred to as corefloods, are widely used to study and understand fluid flow in the subsurface. However, visual inspection of flow in cores requires computed tomography machines which may not be widely accessible. We introduce a novel micromodel that is as long as a typical core (40 cm), has adjustable pore structure, and includes 2.5D pore throats that can be used to conduct fluid displacements analogous to those in cores. Flow can be visualized inexpensively in the micromodel with an optical microscope. We performed standard coreflood tests in our micromodel including a tracer test and a steady state permeability test. We also conducted multiphase displacements by injecting aqueous solutions at varying glycerol concentrations to displace oil from the micromodel and observed the effect of the viscosity ratio on macro-scale recovery efficiency. When the injected aqueous solution was less viscous than the resident oil, it fingered through the oil. Fingering was not observed in the cases where the injected glycerol solution was more viscous than the oil. Moreover, as the viscosity of the injected glycerol solution increased, oil was recovered more rapidly. Additionally, we performed surfactant and glycerol floods in short (2.4 cm) and long (40 cm) micromodels that show long chips capture scale dependent physics, such as oil banking, that small chips do not capture. The novel micromodel shows promise as a screening tool for chemical EOR because it captures phase banks that are desirable in corefloods.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Regulatory requirements for the analysis of 24 elemental impurities (Li, V, Cr, Co, Ni, Cu, As, Se, Mo, Ru, Rh, Pd, Ag, Cd, Sn, Sb, Ba, Os, Ir, Pt, Au, Hg, Tl and Pb) within pharmaceutical products ...are now included in the guidelines of the USP and ICH. Accurately screening all 24 elements in a single analysis is a challenging task due to different physico-chemical properties of the analytes and diverse compositions of available pharmaceuticals. In the present work, a new sample preparation method was developed for accurate analysis of all 24 USP target elements in five oral drug products (terbutaline sulfate tablets, sertraline hydrochloride tablets, cilostazol tablets, rosuvastatin calcium tablets and sitaglipin phosphate/metformin hydrochloride tablets). Method development particularly involved the stabilization and reliable determination of Os, Se and Au. Sample preparation was performed by microwave-assisted acid digestion using aqua regia followed by a two-step dilution procedure. The digest was first diluted with a simple thiourea solution in order to stabilize Os, and then an aliquot was diluted with a diluted acid solution to eliminate the matrix effect of Se and Au before quantitation by ICP-MS. The influences of different digestion solutions and different post-digestion diluents were investigated. The ICP-MS methodology covering the determination of all 24 elements was successfully validated in terms of linearity, accuracy, precision, the LOD and the LOQ. It is expected that the proposed method can be implemented for routine analysis of a broad spectrum of oral drug products, and help official medicine control laboratories in the quality assessment of drug products in the market.
A novel sample preparation strategy was developed for accurate analysis of all 24 USP/ICH target elements in oral drug products.
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(Franch.) Hara is a perennial herb belonging to the Trilliaceae family. Ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS) was used to detect the ...composition of different fractions of
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leaves. Meanwhile, the extracts of different fractions were evaluated for their cytotoxic activities against four selected human cancer cell lines and one human normal epithelial cell line based on the MTT assay method. Multivariate statistical analysis was performed to screen differential compounds and to analyze the distributions between different fractions. Finally, more than 60 compounds were obtained and identified from the different fractions of
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leaves, and the chloroform and n-butanol extracts showed significant cytotoxic effects on these four cancer cells. Several compounds were preliminarily identified from different fractions, including 36 steroidal saponins, 11 flavonoids, 10 ceramides, 8 lipids, 6 organic acids, and 8 other compounds. Various compounds were screened out as different chemical components of different fractions, which were considered as a potential substance basis for the cytotoxicity of
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leaves.
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On-site monitoring of carbamazepine (CBZ) that allows rapid, sensitive, automatic, and high-throughput detection directly from whole blood is of urgent demand in current clinical practice for ...precision medicine. Herein, we developed two types (being indirect vs. direct) of fiber-optic biolayer interferometry (FO-BLI) biosensors for on-site CBZ monitoring. The indirect FO-BLI biosensor preincubated samples with monoclonal antibodies towards CBZ (MA-CBZ), and the mixture competes with immobilized CBZ to bind towards MA-CBZ. The direct FO-BLI biosensor used sample CBZ and CBZ-horseradish peroxidase (CBZ-HRP) conjugate to directly compete for binding with immobilized MA-CBZ, followed by a metal precipitate 3,3'-diaminobenzidine to amplify the signals. Indirect FO-BLI detected CBZ within its therapeutic range and was regenerated up to 12 times with negligible baseline drift, but reported results in 25 min. However, Direct FO-BLI achieved CBZ detection in approximately 7.5 min, down to as low as 10 ng/mL, with good accuracy, specificity and negligible matric interference using a high-salt buffer. Validation of Direct FO-BLI using six paired sera and whole blood from epileptic patients showed excellent agreement with ultra-performance liquid chromatography. Being automated and able to achieve high throughput, Direct FO-BLI proved itself to be more effective for integration into the clinic by delivering CBZ values from whole blood within minutes.
Zhenwu Decoction (ZWD), a classic formula from Zhang Zhongjing's "Treatise on Typhoid Fever" in the Han Dynasty, consists of five traditional Chinese medicines: Aconiti Lateralis Radix Praeparata ...(ALRP), Paeoniae Radix Alba, Poria Cocos, Ginger, and Rhizoma Atractylodis Macrocephalae. To evaluate the chemical constituent consistency of ZWD before and after compatibility, an ultra-performance liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry was established to comprehensively study the constituents of ZWD. By normalizing the peak area, the pairwise compatibility of ALRP and the other four medicinal herbs, as well as the compatibility of the entire formula were studied, respectively. Multivariate statistical analysis was used to identify the differences. The processed data were analyzed by principal component analysis and supervised orthogonal partial least squared discriminant analysis, and an S-plot was generated to compare the differences in the chemical composition of the two types of decoction samples. The results showed that during the decoction process of ZWD, a total of seven components were recognized as differential compounds before and after compatibility of ZWD, namely 6-gingerol, zingerone, benzoylhypaconine, hypaconitine, benzoylaconine, paeoniflorin and fuziline. The results of this study provide basic data reference for understanding the law of ZWD compatibility and are valuable for the compatibility study of other herbal medicines.
•UPLC-ESI-Q-TOF-MS/MS based metabolomics method was developed.•The chemical consistency of ZWD before and after compatibility were evaluated.•Eleven differential compounds were found in four herb-pairs.•Seven differential compounds were found in ZWD.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•This review focuses on terpenoids extracted from essential oils.•Terpenoids have enantiomers with distinct physiological activities.•Predominant extraction methods are HD, SFME, HS-SPME and ...supercritical fluid.•2D GC is found to have stronger chiral chromatography resolution ability.•Specific distribution and enantiomer excess results could be used as quality markers.
Terpenoids possess significant physiological activities and are rich in essential oils. Some terpenoids have chiral centers and could form enantiomers with distinct physiological activities. Therefore, the extraction and separation of terpenoids enantiomers are very important and have attracted extensive attention in recent years. Meanwhile, the specific distribution and enantiomer excess results (the excess of one enantiomer over the other in a mixture of enantiomers) could be used as quality markers for illegitimate adulteration, origin identification, and exploring component variations and functional interrelations across different plant tissues. In this study, an overview of the progress in the extraction of terpenoids from essential oils and the separation of their enantiomers over the past two decades has been made. Extraction methods were retrieved by the resultant network visualization findings. The results showed that the predominant methods are hydrodistillation, solvent-free microwave extraction, headspace solid-phase microextraction and supercritical fluid extraction methods. GC–MS combined with chiral chromatography columns is commonly used for the separation of enantiomers, while 2D GC is found to have stronger resolution ability. Finally, some prospects for future research directions in the extraction and separation identification of essential oils are proposed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The flow of multiple fluid phases in porous media often results in trapped droplets of the nonwetting phase. Recent experimental and theoretical studies have suggested that nanoparticle aqueous ...dispersions may be effective at mobilizing trapped droplets of nonwetting fluid (oil) in porous media. Hypotheses to explain the observation include the nanoparticles’ modification of solid wettability, droplet stabilization, and changes in interfacial tension and interface rheology. However, because it is difficult to observe droplet behavior on the pore scale, how those factors contribute to oil droplet mobilization has not been fully understood. In this work, we investigated the nanoparticles’ role in nanoparticle-based improved recovery of the nonwetting phase through the direct observation of the mobilization of trapped oil droplets in microfluidic structures that mimic pore–throat geometries. A microfluidic platform was constructed for this study, on which different displacing liquids including aqueous surfactant solutions and nanoparticle suspensions were tested. We found that the nanoparticle concentration is positively related to the oil mobilization efficiency. An approximate mathematical model for calculating the maximum size of an oil droplet trapped in a pore–throat geometry for a fixed flow rate matches the experiment result for displacing liquid with no nanoparticles. The model still holds when the nanoparticle suspension is a displacing liquid. We concluded that nanoparticles mobilize oil in these geometries in a mechanism similar to that for surfactants, which is an increase in capillary number rather than an effect of other fluidic or interfacial properties such as the dynamics adsorption of nanoparticle or dilational rheology of a nanoparticle-adsorbed interface.
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